[v3] power: reset: at91-reset: add sysfs interface to the power on reason
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Message ID 20191209094329.45638-1-kamel.bouhara@bootlin.com
State New
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Series
  • [v3] power: reset: at91-reset: add sysfs interface to the power on reason
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Commit Message

Kamel Bouhara Dec. 9, 2019, 9:43 a.m. UTC
This patch export the power on reason through the sysfs interface and
introduce some generic reset sources.
Update the ABI documentation to list current power on sources.

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
---
Changes in v2
=============
	- Be less specific on the crystal oscillator value
	- Add an Acked-by
Changes in v3
=============
	- Really be less specific on the crystal oscillator value

 .../sysfs-devices-platform-power-on-reason    | 14 ++++++
 drivers/power/reset/at91-reset.c              | 44 +++++++++++++------
 include/linux/power/power_on_reason.h         | 19 ++++++++
 3 files changed, 64 insertions(+), 13 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
 create mode 100644 include/linux/power/power_on_reason.h

--
2.24.0

Comments

Claudiu Beznea Dec. 9, 2019, 11:33 a.m. UTC | #1
Hi Kamel,

On 09.12.2019 11:43, Kamel Bouhara wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> This patch export the power on reason through the sysfs interface and
> introduce some generic reset sources.
> Update the ABI documentation to list current power on sources.
> 
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> ---
> Changes in v2
> =============
>         - Be less specific on the crystal oscillator value
>         - Add an Acked-by
> Changes in v3
> =============
>         - Really be less specific on the crystal oscillator value
> 
>  .../sysfs-devices-platform-power-on-reason    | 14 ++++++
>  drivers/power/reset/at91-reset.c              | 44 +++++++++++++------
>  include/linux/power/power_on_reason.h         | 19 ++++++++
>  3 files changed, 64 insertions(+), 13 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
>  create mode 100644 include/linux/power/power_on_reason.h
> 
> diff --git a/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> new file mode 100644
> index 000000000000..83daeb9b1aa2
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> @@ -0,0 +1,14 @@
> +What:          /sys/devices/platform/.../power_on_reason
> +
> +Date:          October 2019
> +KernelVersion: 5.4
> +Contact:       Kamel Bouhara <kamel.bouhara@bootlin.com>
> +Description:   This file shows system power on reason.
> +               The possible sources are:
> +               General System Power-ON, RTC wakeup, Watchdog timeout,
> +               Software Reset, User pressed reset button,
> +               CPU Clock failure, 32.768kHz Oscillator Failure,

Crystal oscillator value is still present here.

> +               Low power mode exit, Unknown.
> +
> +               The file is read only.
> +
> diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
> index 44ca983a49a1..3cb2df40af37 100644
> --- a/drivers/power/reset/at91-reset.c
> +++ b/drivers/power/reset/at91-reset.c
> @@ -17,7 +17,7 @@
>  #include <linux/of_address.h>
>  #include <linux/platform_device.h>
>  #include <linux/reboot.h>
> -
> +#include <linux/power/power_on_reason.h>

As far as I know, headers in include/linux are only visible in kernel.
Although you may use this header, in future, in other drivers (as Alexandre
specified in a previous email), at the moment it is only used by
at91-reset.c. So, why not keeping them in at91-reset.c or leave it as is
for the moment and introduce it when this will be necessary?

Moreover, you are doing 2 things on a patch:
1/ export the reset reasons through sysfs
2/ introduce the reset reason defines

Thank you,
Claudiu Beznea

>  #include <soc/at91/at91sam9_ddrsdr.h>
>  #include <soc/at91/at91sam9_sdramc.h>
> 
> @@ -146,42 +146,42 @@ static int samx7_restart(struct notifier_block *this, unsigned long mode,
>         return NOTIFY_DONE;
>  }
> 
> -static void __init at91_reset_status(struct platform_device *pdev)
> +static const char *at91_reset_reason(struct platform_device *pdev)
>  {
>         const char *reason;
>         u32 reg = readl(at91_rstc_base + AT91_RSTC_SR);
> 
>         switch ((reg & AT91_RSTC_RSTTYP) >> 8) {
>         case RESET_TYPE_GENERAL:
> -               reason = "general reset";
> +               reason = POWER_ON_REASON_GENERAL;
>                 break;
>         case RESET_TYPE_WAKEUP:
> -               reason = "wakeup";
> +               reason = POWER_ON_REASON_RTC;
>                 break;
>         case RESET_TYPE_WATCHDOG:
> -               reason = "watchdog reset";
> +               reason = POWER_ON_REASON_WATCHDOG;
>                 break;
>         case RESET_TYPE_SOFTWARE:
> -               reason = "software reset";
> +               reason = POWER_ON_REASON_SOFTWARE;
>                 break;
>         case RESET_TYPE_USER:
> -               reason = "user reset";
> +               reason = POWER_ON_REASON_USER;
>                 break;
>         case RESET_TYPE_CPU_FAIL:
> -               reason = "CPU clock failure detection";
> +               reason = POWER_ON_REASON_CPU_FAIL;
>                 break;
>         case RESET_TYPE_XTAL_FAIL:
> -               reason = "32.768 kHz crystal failure detection";
> +               reason = POWER_ON_REASON_XTAL_FAIL;
>                 break;
>         case RESET_TYPE_ULP2:
> -               reason = "ULP2 reset";
> +               reason = POWER_ON_REASON_LOW_POWER;
>                 break;
>         default:
> -               reason = "unknown reset";
> +               reason = POWER_ON_REASON_UNKNOWN;
>                 break;
>         }
> 
> -       dev_info(&pdev->dev, "Starting after %s\n", reason);
> +       return reason;
>  }
> 
>  static const struct of_device_id at91_ramc_of_match[] = {
> @@ -204,6 +204,17 @@ static struct notifier_block at91_restart_nb = {
>         .priority = 192,
>  };
> 
> +static ssize_t power_on_reason_show(struct device *dev,
> +                                   struct device_attribute *attr,
> +                                   char *buf)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +
> +       return sprintf(buf, "%s\n", at91_reset_reason(pdev));
> +}
> +
> +static DEVICE_ATTR_RO(power_on_reason);
> +
>  static int __init at91_reset_probe(struct platform_device *pdev)
>  {
>         const struct of_device_id *match;
> @@ -248,7 +259,14 @@ static int __init at91_reset_probe(struct platform_device *pdev)
>                 return ret;
>         }
> 
> -       at91_reset_status(pdev);
> +       ret = device_create_file(&pdev->dev, &dev_attr_power_on_reason);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Could not create sysfs entry\n");
> +               return ret;
> +       }
> +
> +       dev_info(&pdev->dev, "Starting after %s reset\n",
> +                at91_reset_reason(pdev));
> 
>         return 0;
>  }
> diff --git a/include/linux/power/power_on_reason.h b/include/linux/power/power_on_reason.h
> new file mode 100644
> index 000000000000..9c44baa52911
> --- /dev/null
> +++ b/include/linux/power/power_on_reason.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Author: Kamel Bouhra <kamel.bouhara@bootlin.com>
> + */
> +
> +#ifndef POWER_ON_REASON_H
> +#define POWER_ON_REASON_H
> +
> +#define POWER_ON_REASON_GENERAL "General"
> +#define POWER_ON_REASON_RTC "RTC wakeup"
> +#define POWER_ON_REASON_WATCHDOG "Watchdog timeout"
> +#define POWER_ON_REASON_SOFTWARE "Software"
> +#define POWER_ON_REASON_USER "User"
> +#define POWER_ON_REASON_CPU_FAIL "CPU clock Failure"
> +#define POWER_ON_REASON_XTAL_FAIL "Crystal oscillator Failure"
> +#define POWER_ON_REASON_LOW_POWER "Low power exit"
> +#define POWER_ON_REASON_UNKNOWN "Unknown"
> +
> +#endif /* POWER_ON_REASON_H */
> --
> 2.24.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
Kamel Bouhara Dec. 9, 2019, 1:44 p.m. UTC | #2
On Mon, Dec 09, 2019 at 11:33:23AM +0000, Claudiu.Beznea@microchip.com wrote:
> Hi Kamel,
>
> On 09.12.2019 11:43, Kamel Bouhara wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> >
> > This patch export the power on reason through the sysfs interface and
> > introduce some generic reset sources.
> > Update the ABI documentation to list current power on sources.
> >
> > Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> > Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> > ---
> > Changes in v2
> > =============
> >         - Be less specific on the crystal oscillator value
> >         - Add an Acked-by
> > Changes in v3
> > =============
> >         - Really be less specific on the crystal oscillator value
> >
> >  .../sysfs-devices-platform-power-on-reason    | 14 ++++++
> >  drivers/power/reset/at91-reset.c              | 44 +++++++++++++------
> >  include/linux/power/power_on_reason.h         | 19 ++++++++
> >  3 files changed, 64 insertions(+), 13 deletions(-)
> >  create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> >  create mode 100644 include/linux/power/power_on_reason.h
> >
> > diff --git a/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> > new file mode 100644
> > index 000000000000..83daeb9b1aa2
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> > @@ -0,0 +1,14 @@
> > +What:          /sys/devices/platform/.../power_on_reason
> > +
> > +Date:          October 2019
> > +KernelVersion: 5.4
> > +Contact:       Kamel Bouhara <kamel.bouhara@bootlin.com>
> > +Description:   This file shows system power on reason.
> > +               The possible sources are:
> > +               General System Power-ON, RTC wakeup, Watchdog timeout,
> > +               Software Reset, User pressed reset button,
> > +               CPU Clock failure, 32.768kHz Oscillator Failure,
>
> Crystal oscillator value is still present here.
>

Indeed, thanks.

> > +               Low power mode exit, Unknown.
> > +
> > +               The file is read only.
> > +
> > diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
> > index 44ca983a49a1..3cb2df40af37 100644
> > --- a/drivers/power/reset/at91-reset.c
> > +++ b/drivers/power/reset/at91-reset.c
> > @@ -17,7 +17,7 @@
> >  #include <linux/of_address.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/reboot.h>
> > -
> > +#include <linux/power/power_on_reason.h>
>
> As far as I know, headers in include/linux are only visible in kernel.
> Although you may use this header, in future, in other drivers (as Alexandre
> specified in a previous email), at the moment it is only used by
> at91-reset.c. So, why not keeping them in at91-reset.c or leave it as is
> for the moment and introduce it when this will be necessary?
>

Well, It's been a while now the idea was proposed, I've just submitted
it here.

> Moreover, you are doing 2 things on a patch:
> 1/ export the reset reasons through sysfs
> 2/ introduce the reset reason defines
>
Ok, I shall split it in two patches, if it could clarify things ?

> Thank you,
> Claudiu Beznea
>
> >  #include <soc/at91/at91sam9_ddrsdr.h>
> >  #include <soc/at91/at91sam9_sdramc.h>
> >
> > @@ -146,42 +146,42 @@ static int samx7_restart(struct notifier_block *this, unsigned long mode,
> >         return NOTIFY_DONE;
> >  }
> >
> > -static void __init at91_reset_status(struct platform_device *pdev)
> > +static const char *at91_reset_reason(struct platform_device *pdev)
> >  {
> >         const char *reason;
> >         u32 reg = readl(at91_rstc_base + AT91_RSTC_SR);
> >
> >         switch ((reg & AT91_RSTC_RSTTYP) >> 8) {
> >         case RESET_TYPE_GENERAL:
> > -               reason = "general reset";
> > +               reason = POWER_ON_REASON_GENERAL;
> >                 break;
> >         case RESET_TYPE_WAKEUP:
> > -               reason = "wakeup";
> > +               reason = POWER_ON_REASON_RTC;
> >                 break;
> >         case RESET_TYPE_WATCHDOG:
> > -               reason = "watchdog reset";
> > +               reason = POWER_ON_REASON_WATCHDOG;
> >                 break;
> >         case RESET_TYPE_SOFTWARE:
> > -               reason = "software reset";
> > +               reason = POWER_ON_REASON_SOFTWARE;
> >                 break;
> >         case RESET_TYPE_USER:
> > -               reason = "user reset";
> > +               reason = POWER_ON_REASON_USER;
> >                 break;
> >         case RESET_TYPE_CPU_FAIL:
> > -               reason = "CPU clock failure detection";
> > +               reason = POWER_ON_REASON_CPU_FAIL;
> >                 break;
> >         case RESET_TYPE_XTAL_FAIL:
> > -               reason = "32.768 kHz crystal failure detection";
> > +               reason = POWER_ON_REASON_XTAL_FAIL;
> >                 break;
> >         case RESET_TYPE_ULP2:
> > -               reason = "ULP2 reset";
> > +               reason = POWER_ON_REASON_LOW_POWER;
> >                 break;
> >         default:
> > -               reason = "unknown reset";
> > +               reason = POWER_ON_REASON_UNKNOWN;
> >                 break;
> >         }
> >
> > -       dev_info(&pdev->dev, "Starting after %s\n", reason);
> > +       return reason;
> >  }
> >
> >  static const struct of_device_id at91_ramc_of_match[] = {
> > @@ -204,6 +204,17 @@ static struct notifier_block at91_restart_nb = {
> >         .priority = 192,
> >  };
> >
> > +static ssize_t power_on_reason_show(struct device *dev,
> > +                                   struct device_attribute *attr,
> > +                                   char *buf)
> > +{
> > +       struct platform_device *pdev = to_platform_device(dev);
> > +
> > +       return sprintf(buf, "%s\n", at91_reset_reason(pdev));
> > +}
> > +
> > +static DEVICE_ATTR_RO(power_on_reason);
> > +
> >  static int __init at91_reset_probe(struct platform_device *pdev)
> >  {
> >         const struct of_device_id *match;
> > @@ -248,7 +259,14 @@ static int __init at91_reset_probe(struct platform_device *pdev)
> >                 return ret;
> >         }
> >
> > -       at91_reset_status(pdev);
> > +       ret = device_create_file(&pdev->dev, &dev_attr_power_on_reason);
> > +       if (ret) {
> > +               dev_err(&pdev->dev, "Could not create sysfs entry\n");
> > +               return ret;
> > +       }
> > +
> > +       dev_info(&pdev->dev, "Starting after %s reset\n",
> > +                at91_reset_reason(pdev));
> >
> >         return 0;
> >  }
> > diff --git a/include/linux/power/power_on_reason.h b/include/linux/power/power_on_reason.h
> > new file mode 100644
> > index 000000000000..9c44baa52911
> > --- /dev/null
> > +++ b/include/linux/power/power_on_reason.h
> > @@ -0,0 +1,19 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Author: Kamel Bouhra <kamel.bouhara@bootlin.com>
> > + */
> > +
> > +#ifndef POWER_ON_REASON_H
> > +#define POWER_ON_REASON_H
> > +
> > +#define POWER_ON_REASON_GENERAL "General"
> > +#define POWER_ON_REASON_RTC "RTC wakeup"
> > +#define POWER_ON_REASON_WATCHDOG "Watchdog timeout"
> > +#define POWER_ON_REASON_SOFTWARE "Software"
> > +#define POWER_ON_REASON_USER "User"
> > +#define POWER_ON_REASON_CPU_FAIL "CPU clock Failure"
> > +#define POWER_ON_REASON_XTAL_FAIL "Crystal oscillator Failure"
> > +#define POWER_ON_REASON_LOW_POWER "Low power exit"
> > +#define POWER_ON_REASON_UNKNOWN "Unknown"
> > +
> > +#endif /* POWER_ON_REASON_H */
> > --
> > 2.24.0
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >

--
Kamel Bouhara, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
Sebastian Reichel Dec. 19, 2019, 5:13 p.m. UTC | #3
Hi,

On Mon, Dec 09, 2019 at 02:44:58PM +0100, Kamel Bouhara wrote:
> On Mon, Dec 09, 2019 at 11:33:23AM +0000, Claudiu.Beznea@microchip.com wrote:
> > On 09.12.2019 11:43, Kamel Bouhara wrote:
> > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> > >
> > > This patch export the power on reason through the sysfs interface and
> > > introduce some generic reset sources.
> > > Update the ABI documentation to list current power on sources.
> > >
> > > Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> > > Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> > > ---
> > > Changes in v2
> > > =============
> > >         - Be less specific on the crystal oscillator value
> > >         - Add an Acked-by
> > > Changes in v3
> > > =============
> > >         - Really be less specific on the crystal oscillator value
> > >
> > >  .../sysfs-devices-platform-power-on-reason    | 14 ++++++
> > >  drivers/power/reset/at91-reset.c              | 44 +++++++++++++------
> > >  include/linux/power/power_on_reason.h         | 19 ++++++++
> > >  3 files changed, 64 insertions(+), 13 deletions(-)
> > >  create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> > >  create mode 100644 include/linux/power/power_on_reason.h
> > >
> > > diff --git a/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> > > new file mode 100644
> > > index 000000000000..83daeb9b1aa2
> > > --- /dev/null
> > > +++ b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
> > > @@ -0,0 +1,14 @@
> > > +What:          /sys/devices/platform/.../power_on_reason
> > > +
> > > +Date:          October 2019
> > > +KernelVersion: 5.4
> > > +Contact:       Kamel Bouhara <kamel.bouhara@bootlin.com>
> > > +Description:   This file shows system power on reason.
> > > +               The possible sources are:
> > > +               General System Power-ON, RTC wakeup, Watchdog timeout,
> > > +               Software Reset, User pressed reset button,
> > > +               CPU Clock failure, 32.768kHz Oscillator Failure,
> >
> > Crystal oscillator value is still present here.
> >
> 
> Indeed, thanks.
> 
> > > +               Low power mode exit, Unknown.
> > > +
> > > +               The file is read only.
> > > +
> > > diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
> > > index 44ca983a49a1..3cb2df40af37 100644
> > > --- a/drivers/power/reset/at91-reset.c
> > > +++ b/drivers/power/reset/at91-reset.c
> > > @@ -17,7 +17,7 @@
> > >  #include <linux/of_address.h>
> > >  #include <linux/platform_device.h>
> > >  #include <linux/reboot.h>
> > > -
> > > +#include <linux/power/power_on_reason.h>
> >
> > As far as I know, headers in include/linux are only visible in kernel.
> > Although you may use this header, in future, in other drivers (as Alexandre
> > specified in a previous email), at the moment it is only used by
> > at91-reset.c. So, why not keeping them in at91-reset.c or leave it as is
> > for the moment and introduce it when this will be necessary?
> >
> 
> Well, It's been a while now the idea was proposed, I've just submitted
> it here.
> 
> > Moreover, you are doing 2 things on a patch:
> > 1/ export the reset reasons through sysfs
> > 2/ introduce the reset reason defines
>
> Ok, I shall split it in two patches, if it could clarify things ?

Yes, please split into two patches.

> > Thank you,
> > Claudiu Beznea
> >
> > >  #include <soc/at91/at91sam9_ddrsdr.h>
> > >  #include <soc/at91/at91sam9_sdramc.h>
> > >
> > > @@ -146,42 +146,42 @@ static int samx7_restart(struct notifier_block *this, unsigned long mode,
> > >         return NOTIFY_DONE;
> > >  }
> > >
> > > -static void __init at91_reset_status(struct platform_device *pdev)
> > > +static const char *at91_reset_reason(struct platform_device *pdev)
> > >  {
> > >         const char *reason;
> > >         u32 reg = readl(at91_rstc_base + AT91_RSTC_SR);
> > >
> > >         switch ((reg & AT91_RSTC_RSTTYP) >> 8) {
> > >         case RESET_TYPE_GENERAL:
> > > -               reason = "general reset";
> > > +               reason = POWER_ON_REASON_GENERAL;
> > >                 break;
> > >         case RESET_TYPE_WAKEUP:
> > > -               reason = "wakeup";
> > > +               reason = POWER_ON_REASON_RTC;
> > >                 break;
> > >         case RESET_TYPE_WATCHDOG:
> > > -               reason = "watchdog reset";
> > > +               reason = POWER_ON_REASON_WATCHDOG;
> > >                 break;
> > >         case RESET_TYPE_SOFTWARE:
> > > -               reason = "software reset";
> > > +               reason = POWER_ON_REASON_SOFTWARE;
> > >                 break;
> > >         case RESET_TYPE_USER:
> > > -               reason = "user reset";
> > > +               reason = POWER_ON_REASON_USER;
> > >                 break;
> > >         case RESET_TYPE_CPU_FAIL:
> > > -               reason = "CPU clock failure detection";
> > > +               reason = POWER_ON_REASON_CPU_FAIL;
> > >                 break;
> > >         case RESET_TYPE_XTAL_FAIL:
> > > -               reason = "32.768 kHz crystal failure detection";
> > > +               reason = POWER_ON_REASON_XTAL_FAIL;
> > >                 break;
> > >         case RESET_TYPE_ULP2:
> > > -               reason = "ULP2 reset";
> > > +               reason = POWER_ON_REASON_LOW_POWER;
> > >                 break;
> > >         default:
> > > -               reason = "unknown reset";
> > > +               reason = POWER_ON_REASON_UNKNOWN;
> > >                 break;
> > >         }
> > >
> > > -       dev_info(&pdev->dev, "Starting after %s\n", reason);
> > > +       return reason;
> > >  }
> > >
> > >  static const struct of_device_id at91_ramc_of_match[] = {
> > > @@ -204,6 +204,17 @@ static struct notifier_block at91_restart_nb = {
> > >         .priority = 192,
> > >  };
> > >
> > > +static ssize_t power_on_reason_show(struct device *dev,
> > > +                                   struct device_attribute *attr,
> > > +                                   char *buf)
> > > +{
> > > +       struct platform_device *pdev = to_platform_device(dev);
> > > +
> > > +       return sprintf(buf, "%s\n", at91_reset_reason(pdev));
> > > +}
> > > +
> > > +static DEVICE_ATTR_RO(power_on_reason);
> > > +
> > >  static int __init at91_reset_probe(struct platform_device *pdev)
> > >  {
> > >         const struct of_device_id *match;
> > > @@ -248,7 +259,14 @@ static int __init at91_reset_probe(struct platform_device *pdev)
> > >                 return ret;
> > >         }
> > >
> > > -       at91_reset_status(pdev);
> > > +       ret = device_create_file(&pdev->dev, &dev_attr_power_on_reason);
> > > +       if (ret) {
> > > +               dev_err(&pdev->dev, "Could not create sysfs entry\n");
> > > +               return ret;
> > > +       }
> > > +
> > > +       dev_info(&pdev->dev, "Starting after %s reset\n",
> > > +                at91_reset_reason(pdev));
> > >
> > >         return 0;
> > >  }
> > > diff --git a/include/linux/power/power_on_reason.h b/include/linux/power/power_on_reason.h
> > > new file mode 100644
> > > index 000000000000..9c44baa52911
> > > --- /dev/null
> > > +++ b/include/linux/power/power_on_reason.h
> > > @@ -0,0 +1,19 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-only */
> > > +/*
> > > + * Author: Kamel Bouhra <kamel.bouhara@bootlin.com>
> > > + */
> > > +
> > > +#ifndef POWER_ON_REASON_H
> > > +#define POWER_ON_REASON_H
> > > +
> > > +#define POWER_ON_REASON_GENERAL "General"
> > > +#define POWER_ON_REASON_RTC "RTC wakeup"
> > > +#define POWER_ON_REASON_WATCHDOG "Watchdog timeout"
> > > +#define POWER_ON_REASON_SOFTWARE "Software"
> > > +#define POWER_ON_REASON_USER "User"

Is this user reset button from the sysfs file? I think just "User"
is a bit too short. Also please make sure, that the list actually
matches the API described in the documentation :)

-- Sebastian

> > > +#define POWER_ON_REASON_CPU_FAIL "CPU clock Failure"
> > > +#define POWER_ON_REASON_XTAL_FAIL "Crystal oscillator Failure"
> > > +#define POWER_ON_REASON_LOW_POWER "Low power exit"
> > > +#define POWER_ON_REASON_UNKNOWN "Unknown"
> > > +
> > > +#endif /* POWER_ON_REASON_H */
> > > --
> > > 2.24.0
> > >
> > >
> > > _______________________________________________
> > > linux-arm-kernel mailing list
> > > linux-arm-kernel@lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> > >
> 
> --
> Kamel Bouhara, Bootlin
> Embedded Linux and kernel engineering
> https://bootlin.com
Kamel Bouhara Dec. 20, 2019, 10:07 a.m. UTC | #4
On Thu, Dec 19, 2019 at 06:13:14PM +0100, Sebastian Reichel wrote:
> Hi,
>

Hi,

[...]

> >
> > > Moreover, you are doing 2 things on a patch:
> > > 1/ export the reset reasons through sysfs
> > > 2/ introduce the reset reason defines
> >
> > Ok, I shall split it in two patches, if it could clarify things ?
>
> Yes, please split into two patches.
>

OK.

[...]

>
> Is this user reset button from the sysfs file? I think just "User"
> is a bit too short. Also please make sure, that the list actually
> matches the API described in the documentation :)
>

OK, fixed in v4, please check.

Cheers.

Kamel

--
Kamel Bouhara, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

Patch
diff mbox series

diff --git a/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
new file mode 100644
index 000000000000..83daeb9b1aa2
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-platform-power-on-reason
@@ -0,0 +1,14 @@ 
+What:		/sys/devices/platform/.../power_on_reason
+
+Date:		October 2019
+KernelVersion:	5.4
+Contact:	Kamel Bouhara <kamel.bouhara@bootlin.com>
+Description:	This file shows system power on reason.
+		The possible sources are:
+		General System Power-ON, RTC wakeup, Watchdog timeout,
+		Software Reset, User pressed reset button,
+		CPU Clock failure, 32.768kHz Oscillator Failure,
+		Low power mode exit, Unknown.
+
+		The file is read only.
+
diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
index 44ca983a49a1..3cb2df40af37 100644
--- a/drivers/power/reset/at91-reset.c
+++ b/drivers/power/reset/at91-reset.c
@@ -17,7 +17,7 @@ 
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/reboot.h>
-
+#include <linux/power/power_on_reason.h>
 #include <soc/at91/at91sam9_ddrsdr.h>
 #include <soc/at91/at91sam9_sdramc.h>

@@ -146,42 +146,42 @@  static int samx7_restart(struct notifier_block *this, unsigned long mode,
 	return NOTIFY_DONE;
 }

-static void __init at91_reset_status(struct platform_device *pdev)
+static const char *at91_reset_reason(struct platform_device *pdev)
 {
 	const char *reason;
 	u32 reg = readl(at91_rstc_base + AT91_RSTC_SR);

 	switch ((reg & AT91_RSTC_RSTTYP) >> 8) {
 	case RESET_TYPE_GENERAL:
-		reason = "general reset";
+		reason = POWER_ON_REASON_GENERAL;
 		break;
 	case RESET_TYPE_WAKEUP:
-		reason = "wakeup";
+		reason = POWER_ON_REASON_RTC;
 		break;
 	case RESET_TYPE_WATCHDOG:
-		reason = "watchdog reset";
+		reason = POWER_ON_REASON_WATCHDOG;
 		break;
 	case RESET_TYPE_SOFTWARE:
-		reason = "software reset";
+		reason = POWER_ON_REASON_SOFTWARE;
 		break;
 	case RESET_TYPE_USER:
-		reason = "user reset";
+		reason = POWER_ON_REASON_USER;
 		break;
 	case RESET_TYPE_CPU_FAIL:
-		reason = "CPU clock failure detection";
+		reason = POWER_ON_REASON_CPU_FAIL;
 		break;
 	case RESET_TYPE_XTAL_FAIL:
-		reason = "32.768 kHz crystal failure detection";
+		reason = POWER_ON_REASON_XTAL_FAIL;
 		break;
 	case RESET_TYPE_ULP2:
-		reason = "ULP2 reset";
+		reason = POWER_ON_REASON_LOW_POWER;
 		break;
 	default:
-		reason = "unknown reset";
+		reason = POWER_ON_REASON_UNKNOWN;
 		break;
 	}

-	dev_info(&pdev->dev, "Starting after %s\n", reason);
+	return reason;
 }

 static const struct of_device_id at91_ramc_of_match[] = {
@@ -204,6 +204,17 @@  static struct notifier_block at91_restart_nb = {
 	.priority = 192,
 };

+static ssize_t power_on_reason_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	return sprintf(buf, "%s\n", at91_reset_reason(pdev));
+}
+
+static DEVICE_ATTR_RO(power_on_reason);
+
 static int __init at91_reset_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *match;
@@ -248,7 +259,14 @@  static int __init at91_reset_probe(struct platform_device *pdev)
 		return ret;
 	}

-	at91_reset_status(pdev);
+	ret = device_create_file(&pdev->dev, &dev_attr_power_on_reason);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not create sysfs entry\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "Starting after %s reset\n",
+		 at91_reset_reason(pdev));

 	return 0;
 }
diff --git a/include/linux/power/power_on_reason.h b/include/linux/power/power_on_reason.h
new file mode 100644
index 000000000000..9c44baa52911
--- /dev/null
+++ b/include/linux/power/power_on_reason.h
@@ -0,0 +1,19 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Author: Kamel Bouhra <kamel.bouhara@bootlin.com>
+ */
+
+#ifndef POWER_ON_REASON_H
+#define POWER_ON_REASON_H
+
+#define POWER_ON_REASON_GENERAL "General"
+#define POWER_ON_REASON_RTC "RTC wakeup"
+#define POWER_ON_REASON_WATCHDOG "Watchdog timeout"
+#define POWER_ON_REASON_SOFTWARE "Software"
+#define POWER_ON_REASON_USER "User"
+#define POWER_ON_REASON_CPU_FAIL "CPU clock Failure"
+#define POWER_ON_REASON_XTAL_FAIL "Crystal oscillator Failure"
+#define POWER_ON_REASON_LOW_POWER "Low power exit"
+#define POWER_ON_REASON_UNKNOWN "Unknown"
+
+#endif /* POWER_ON_REASON_H */